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ED209

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Everything posted by ED209

  1. Yep, (Ilha de) Tavira turned out to have fantastic views while lazing on the beach. The Milky Way was clearly visible with the naked eye all the way from the southern horizon up to Cygnus (pretty much directly overhead), so far as spotting objects was concerned it was more a case of looking for wispy patches with the naked eye before looking with the binoculars and then only later trying to identify them on the star maps. M7 was amazing and M6 just off to the side were probably the best. All in all a great holiday really, I'm sure we'll go back sometime for some off-season sun
  2. Aw, having had a read of the similar thread linked at the bottom of the page it seems where we're half-planning on going - near Tavira, there's a little island with a campsite on it - has bad LP problems. Still, should beat the view from my backyard anyway. I've printed out (from starcalc) what I hope will be a useable map of the view to the south and jotted down the magnitudes of the Messier objects around there - gonna start looking for M8 as suggested above and then look around there. So how do I best plan to avoid light pollution problems (in terms of the maps I should print and annotate)? Tavira town will be 2 or 3 miles to the NW, across the tidal estuary (so nothing to block the light). From the SW around to the NE it's just going to be sea. Am I right to think that my darkest skies will be centred on the vertical line drawn from the SE horizon to straight up (i.e. with my back to where the town is, everything in front of me), or does light pollution do funny things like bleed around the horizon or reflect back on itself? Sorry if that is the dumbest question of all time but I'm used to a fairly uniform band of LP all around me and I don't know whether it is more complicated than light simply shining up into the sky above the where the light source is, particularly since this is sea air, might be misty and more reflective or something.
  3. Hi All, We're off camping in the Algarve this week, wondering if there is anything particularly worth viewing through binoculars from that southerly latitude? Will have a play in Stellarium before we go but once we've left it'll be whatever starmaps I've printed and binoculars only...just wondering if there is anything that is a 'must-see'. We should have perfectly dark skies out over the sea to the south!
  4. That's a great idea! I'll make one when I get back from me hols
  5. Excellent ideas, I'll give them a go When set up, this ocular plugin for stellarium really will be an excellent tool for a n00b like me
  6. Yeah I've been playing around with that too! Problem is, I've got no idea what the focal length or AFOV of my EPs are, I bought them second hand. This isn't something that can be calculated from available info such as their aperture and the measurements of my scope, is it?
  7. M57 is sooo small, just imagine how big a really small DSO would appear in your selected eyepiece and it's about 1/10th the size of that I managed to find it after a short time spent pointing to roughly where I though it would be and scanning around with my widest EP, more luck than anything else. I'm not good enough to star-hop and in any case I don't have a decent map, just stellarium. There is software, 'star calc' I think it's called, that lets you print out maps to whatever magnification you fancy, but I have no idea what my limiting magnification is currently and I'm waiting for some darker nights before giving it a proper go.
  8. The advantage of youth is that one will often still be up at 3:30 am anyway
  9. I know everyone always says this, but as another recent beginner myself it really is true that you can keep yourself amused with binoculars for ages before you genuinely need a scope. Now naturally I didn't do this either, instead starting with an excellent 2nd hand bargain scope, but rapidly found I needed binoculars anyway to scan the sky for interesting stuff (it's surprising how much more you see in 10x50s, really). If I was starting again, I'd buy some 10x50s and wait for a suitable scope to come up in the For Sale section that's accessibly close to you.
  10. Wow, that's a very nice circle degree mod. I've just taken a sewing tape measure to mine and marked off 10 degree increments around the top of the base...then scribbled a little 'north' arrow on one of the three feet that protudes from the bottom part of my base (which isn't exactly round, but a bulging sort of triangle which gives me a wider base for the rubber feet). Just now I pointed the arrow roughly to Polaris, pointed the telescope to the moon then read the moon's alt/az off stellarium to check the orientation, adjusted the base by just a couple of degrees, looked up Saturn's position on stellarium and put the scope right on it (still using my protractor for the alt) without using the finderscope! Happy with that....now waiting for it to get dark...
  11. Now I've got my scope up and running I'm looking to cheat in every possible way to help me find stuff. It's no doubt a sad reflection of my inexperience but trying to locate messier objects by star-hopping/scanning the approx area gets me fewer results than just holding a protractor against the scope to get a rough guide to the angle! So time to make my dob the ultimate DIY 'push to' I think... I read good things about the Wixey digital inclinometer, but want a cheaper option ()...are the mechanical inclinometers that sell for ~£4 any good? Or should I bite the bullet and go for the 0.1 degree accuracy of the wixey. And another question, does the wixey measure inclination absolutely or relative to the starting point (i.e. do you 'tare' it with the telescope vertical or horizontal and then it reads relative do that point?). I don't think I'd be particularly good at setting it accurately to begin with! Secondly, I fancy marking the base of my dob with angle measurements to give me a rough idea of azimuth. Before I just get a CD label pen and measure out blocks of 5 or 10 degrees by hand, is there a way that I could generate accurately marked circular sections tailored for the size of the dob's base on my PC and print them out, laminate them in plastic and sticking them on? I've tried to print out woodworking plans to precisely the correct scale before for a different kind of project - scaling DPI on my printer etc - and found that to be a bit of a mission TBH. Wondering if I'd be better off to just have a go by hand, would that be accurate enough? Better than nothing, I suppose?
  12. ED209

    Dob bearings

    I didn't know you could stick it effectively if you etched one side, instead I drilled holes through my bearing points, countersunk the holes deeply, and attached them using little screws. It did also occur to me to use silicon lubricant on my dob's base because I started out using felt pads (which were a failure, nowhere near as good as PTFE) - I actually wanted Pledge or something similar, having slipped over like a clown more than once on laminate flooring after someone's been polishing furniture! I don't know how effective the silicon spray really is but between that and three PTFE bearings of about an inch square my dob's azimuth adjustment is as smooth as I could have hoped for, and way smoother than I thought it would be.
  13. ED209

    Dob bearings

    I bought 100mmx100mmx5mm PTFE sheet from peter_pan1981 on ebay, £4 delivered and came very quickly.
  14. That's very interesting. I was wondering how on Earth people ever ground mirrors by hand to be perfectly parabolic, I guess the mirror has only to be somewhere between parabolic and spherical to work to some extent.
  15. I've found and installed Virtual Moon Atlas - how awesome is that programme? A zoomable high-res map of the moon with every point of interest labelled, described physically and its history noted
  16. Thanks - that's definitely it Looks good at 100x, I think Well I never - it's a gentle slope that happens to be lit from a perfect angle, and not a cliff at all. Well, I suppose 1:10 is actually quite a steep slope, not so easy to cycle up...except perhaps on the surface of the moon....
  17. Gazing idly at the moon I've just noticed a feature of comparative interest (to us anyway! ), and I'm wondering what it is? It's easy to find right now. Near the terminator about one third up from the bottom (as orientated to the naked eye) there is a quite a big crater almost all the way across the flat bottom of which is a very sharp, very crisp long shadow. From its direction, it look like the shadow of a very long rift or crack that has the side nearest the sun much higher than the other, so that it casts a wide crisp shadow. But, the rift seems bounded by (and so younger than) the crater. Whatever it is, it was plonked in place as we see it now (i.e it's not a fragment of a bigger larger feature, like a very prominent ray or somesuch). Does this whatsit have a name, and what do we reckon caused it?
  18. I don't know about this Brian Cox fella but I watched Cosmos recently with the Mrs, it truly is incredible; informative, moving, inspiring (and is pretty much the main reason we now have an 8" dob and I'm posting here ). Apparently when it was originally shown viewing figures amounted to 3% of the population of the Earth. Carl Sagan was perhaps the greatest popular communicator of astronomy, science and rationalism of modern times and is sorely missed. Bearing in mind his quote about how short-sighted and dangerous it is that in the nuclear age we have arranged society such that almost noone understands anything at all of science, I've been ordering my friends and colleagues to watch Cosmos also. I am also particularly fond of his beige suits, Kermit-like voice and peculiar pronunciation of familiar words
  19. Thanks, that's exactly the bit I mean (don't know why I didn't think of posting a picture, would have saved some typing ).
  20. Thanks folks....I bought them online so returning them is a bit inconvenient, I want to be using them on the lovely clear nights we have here this week and it'll probably be the weekend before I'd get a chance to get down the post office. I'll give the shop a call tomorrow, hopefully they'll be able to confirm whether or not they can be tightened up in the way we imagine, and if so I'm sure I'll be able to get them in a state I'm happy with.
  21. Thanks but that not what I mean - yeah the twist-up eye relief rings (that these have instead of rubber eyecups) are a bit waggly, but the whole eyepiece assembly is as well... So when you focus them, a bar that the focussing wheel rotates on slides up and down. Stuck on the end of this bar is a hinged piece (hinged so that the binoculars can be adjusted for different nose widths) that is pushed up and down by this focussing bar. The hinge itself is pretty solid, no flex or play there but the whole hinged piece rocks left and right on the focussing bar such that when you push lightly down on the right eyepiece, it moves 3mm down relative to the body of the binoculars and the left eyepiece moves up 3mm. It's as though this hinged piece should be more tightly screwed down to the focussing bar (there isn't a screw visible or accessible - the area is covered by a rubber plug that appears glued on and I don't want to pick off in case I end up returning them, but I presume there is a screw under there).
  22. Hi All I've just bought some cheap - well £30, they're cheaper when on at Lidl but I didn't want to wait - 10x50s and am surprised by the amount of play in the eyepieces. At all positions of focus, the eyepieces waggle left and right on the focussing bar (the bit that slides in and out to focus the binoculars) with the tiniest pressure, sliding up and down through 3mm as measured on the outside of the tubes that they slide up and down on (yeah, I've got no clue what the various components are called, sorry!) Having only used a pair of compact 10x25s with fixed tubes (the focussing mechanism being internal) that I've grown accustomed to holding right against my eye sockets for extra stability, I wonder if my 10x50s are dodgy - I have to hold them away from my eyes to maintain focus, not sure if that is normal or not? Should I see about sending them back, or put up with it? If this is par for the course then I'm sure I can get used to it, I'm just wondering if they generally are better put-together and I've got a duff pair... They're Adler Optics Witnesses if that makes any difference (I understand all cheap binoculars are made to similar designs in the same factory, and just branded differently).
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